Remote control of motors



June 12, 1934. c. c. LANE 1,962,354

REMOTE CONTROL OF MOTORS Filed April 7, 1933 CENTRAL OFFICE INVENTOR C.C. LANE AT7URNEV Patented June 12, 1934 UNITED STATES PATENT OFFICE BellTelephone Laboratories, Incorporated,

New York, N. Y., a corporation of New York Application April 7, 1933,Serial No. 664,889

8 Claims.

This invention relates to a communication system and improved apparatusfor controlling motors at remote points. More particularly, it relatesto printing telegraph systems of the light traffic type in which thelocal power supplies for the motors at subscribers printing telegraphstations are arranged to be remotely controlled. However, it is to beunderstood that this invention is not to be limited to printingtelegraph sys- 1O tems.

In a communication system where the demands on distant motors are notcontinuous, such as in a light traflio printing telegraph system, it isdesirable to operate the motors only when the working of the systemrequires such operation.

This will reduce current consumption and maintenance expense. Severaltypes of arrangements have been developed for performing this function.

However, for systems in which the transmission lines are normallyclosed, it has been found that, in the case of those arrangements whichare designed to start motors in response to the closure of thetransmission lines following a short open period, false operation mayoccur. For example, if a switchboard operator should stop the motor at asubscribers station and in withdrawing the plug from the line jack causea momentary interruption of line current, the motor at the subscribersstation would start and continue to run without the knowledge of theswitchboard operator. This false operation might also be caused by theswinging together of open wire lines, by an induced surge of current dueto lightning, or to any other cause which would result in a momentarycessation of line current. This false operation of remotely controlledmotors is objectionable in that a motor at a subscribers station may becaused to start and continue to run 40 withoutthe knowledge of theswitchboard operator thereby wasting current from the power supply atthat particular station as well as causing needless wear of the printingtelegraph machine at that station.

It is an object of the present invention to provide an improvedarrangement for starting and stopping motors at remote points.

It is also an object of this invention to reduce the amount of falseoperation of motors controlled from a remote point.

The preferred form of the invention will be described as applied to aprinting telegraph system in which the transmission lines are normallyclosed.

It is to be understood that the invention is not limited either to asystem in which the transmission lines are normally closed or to aprinting telegraph system.

The objects of this invention are accomplished by means of a specialrelay added to each subscribers station, at which the motor is to beremotely controlled, and connected into the transmission line leadingfrom that station to the oentral exchange office. This relay has aspecially designed armature which co-acts with a plurality of pawls.After the operator at the central office has successively opened andclosed the transmission line leading to a particular subscribers sta'tion a preassigned number of times, the armature of the special relay atthat subscribers station will release the pawls which will close a pathfrom the power supply at that station to the printer motor also at thatstation thereby starting the operation of the motor.

The operator at the central oflice may stop the operation of the motorby transmitting a special signal to that particular subscribers station.This special signal actuates instrumentalities at the subscribersstation which open the path from the power supply to the motor andrestore so the special relay and pawls to their normal con dition.

The invention may be better described with reference to the singlefigure of the drawing which represents a printing telegraph systemarranged in accordance with this invention. Printing telegraph station 1is connected by means ofv a normally closed loop to printing telegraphstation 2 which, for the purpose of illustration, may be assumed to be acentral office. Signal impulses so may be sent from central office 2 outover a normally closed transmission line to station 1, through thesubscribers line relay 3, sending contacts 4, break key 5, special relay6, and'then back over a normally closed transmission line to centraloffice 2.

Although only one printing telegraph station 1 is shown to be connectedto central office 2, it is to be understood that this has been done forthe sake of simplicity and that any desired number of printing telegraphstations may be connected by loops to central office 2. A special relaywith its associated apparatus should be connected into the transmissionline at each station at which the motor is to be remotely controlled. I

As can be seen in the drawing, the armature 7 of special relay 6 ispivoted at one end. The other end of armature '7 has a projection 8attached thereto. Projection 8 is, under the normal con ditions shown inthe drawing, normally engaged 110 with a tooth 9 of pawl 10 attached tolever 11. Lever 11 is maintained in its elevated position by reason oftooth 9 of pawl 10 engaging with projection 8 of armature '7. Pawl 10 ismaintained in a nearly vertical position by means of spring roller 12.Also, under normal conditions the path from the source of power supply13 through motor 14 of the printing telegraph set located at station 1is open due to the upper set of contacts of switch 15 being in theiropen position thus causing motor 14 to be normally non-operated sincepower supply 13 is normally inoperative.

When the operator at central oilice 2 wishes to render power supply 13operative and to start motor 14 in order to communicate with thesubscriber at station 1, she momentarily opens the loop to station 1.The opening of the loop causes special relay 6 to release. Sincearmature '7 of relay 6 has a biasing spring 16 attached to it, whenrelay 6 releases, spring 16 will pull armature 7 to the left. Thisaction will cause projection 8 of armature '7 to disengage from tooth 9of pawl 10 and to engage with tooth 1'1 of pawl 18. This will enableboth pawls 10 and 18, as well as lever 11, to move down one step. Whenthe line closes again (the operator at central ofiice 2 only opened itmomentarily) relay 6 will again become energized and, since the force ofits attraction is greater than the pull exerted by spring 16, armature 7will be pulled to the right. This action will cause projection 8 todisengage from tooth 17 of pawl 18 and to engage with tooth 19 of pawl10. This will enable both pawls 10 and 18 and lever 11 to move down onemore step.

The operator at central oflice 2 again momentarily opens the line tostation 1. Relay 6 again releases and spring 16 again pulls armature '7to the left. This will cause projection 8 to disengage from tooth 19 ofpawl 10 and to engage with tooth 26 of pawl 18 thereby enabling pawls 10and 18 and lever 11 to again move down one more step. On the followingclosure of the line, relay 6 will again pull armature 7 to the rightthereby dis engaging projection 8 from tooth 20 of pawl 18 and causingit to engage with tooth 21 of pawl 10 thus letting pawls 10 and 18 andlever 11 move down an additional step.

This process of operation could be continued as long as desired providedthat there were sufl1- cient teeth on pawls 1i) and 18 and provided thatnothing impeded the downward progress of pawls l0 and 18 and lever 11.However, to simplify matters, it may be assumed that the preassignedsignal to be used by the operator at central office 2 for the purpose ofstarting the motor at station 1 consists of three successive openings ofthe transmission line leading to station 1. Usually these three openingsof the loop to station 1 would be of brief duration but they need notnecessarily be so.

Upon the third successive opening of the loop leading to station 1,relay 6 will release, spring 16 will pull armature '1 to the left,projection 8 will disengage from tooth 21 of pawl 10 and will engagewith tooth 22 of pawl 18, and pawls 10 and 18 and lever 11 will movedown one more step. Then, when the loop is closed again, relay 6 willpull armature 7 to the right, projection 8 will disengage from tooth 22of pawl 18, since in this case there are only three teeth on pawl 10,projection 8 will swing free from pawls 10 and 18.

Since the teeth of pawls 10 and 18 no longer engage with projection 8,pawls 10 and 18 are free to fall down. However, they will still bemaintained in a nearly vertical position by means of spring rollers 12and 23. When pawls 10 and 18 fall down, lever 11 falls with them.However, lever 11 does not fall far before its contact 24 closes switch15. Biasing spring 25 is attached to lever 11 in order to insure theclosing of switch 15. As soon as switch 15 is closed, the downwardprogress of pawls 10 and 18 and lever 11 will be impeded and stopped.

The closure of switch 15 results in the closing of both sets of itscontacts. The lower set of contacts of switch 15 close a short-circuitwhich has the effect of shunting special relay 6 out of the loop circuitso that relay 6 will not be affected by subsequent openings and closuresof the loop. This need not necessarily be done, but it is advisable inorder to save wear and tear on relay 6 and spring 16. The top set ofcontacts of switch 15 close a path leading from power supply 13, throughmotor 14, and then back to power supply 13. This will render powersupply 13 operative and will start motor 14. Cornmunication betweencentral office 2 and station 1 may now take place.

When communication between central oiiice 2 shown) of the printingtelegraph apparatus at 7 station 1.

The closing of contact 26 closes a path leading from power supply 13,through contact 26, through relay 28, and then back to power supply 13.This will energize relay 28, and, since the force of the attraction ofrelay 28 is greater than the pull exerted by spring 25, lever 11 will bepulled up into its elevated position. When lever 11 is pulled up, switch15 will open allowing its double set of contacts to open. The top set ofcontacts of switch 15 will open the path from power supply 13 throughmotor 14. This will cause power supply 13 to become inoperative and willcause the non-operation of motor 14. The

bottom set of contacts of switch 15 will open the v short-circuit acrossrelay 6. normally closed, relay 6 will accordingly be energized and pullits armature '7 over to the right. Lever 11, when it is pulled up byrelay 28, also pushes pawls 10 and 18 up into their normal Since theloop is spring 29, and to be kept apart by stop 30. The invention is notlimited to this particular construction but includes any other suitablearrangement. In fact, it is to be understood that the arrangements shownin the drawing and de scribed above are illustrative of the operation vof the invention and are given in order to serve to assist ininterpreting the claims. The claims are not to be restricted to theprecise construction described above, but are intended to include allchanges and modifications within their scope which employ the principlesand features of operation of the invention.

What is claimed is:

1. A communication system having a near and a remote stationinterconnected by a transmission line, the remote station having a motorand a normally inoperative source of power supply for operating themotor, said system having a remote control arrangement for rendering thenormally inoperative source of power supply operative and for startingthe motor at the remote station in response to the reception ofpreassigned signal impulses transmitted by the near station over thetransmission line, instrumentalities for reducing the amount of falseoperation of the remote control arrangement caused by externaldisturbances affecting the transmission line, and apparatus fordisconnecting the source of power supply from the motor after havingbeen connected thereto, said apparatus being operated in response to thereception at the remote station of a preassigned disconnect signaltransmitted from the near station.

2. A printing telegraph system having a near and a remote printingtelegraph station interconnected by a telegraph line, the remote stationhaving a motor and a normally inoperative source of power supply foroperating the motor, said system having a remote control arrangement forrendering the normally inoperative source of power supply operative andfor starting the motor at the remote station in response to a pluralityof successive openings and closures of the telegraph line by an operatorat the near station, instrumentalities for reducing the amount or" falseoperation of the remote control arrangement caused by externaldisturbances affecting the transmission line, and apparatus fordisconnecting the source of power supply from the motor after havingbeen connected thereto, said apparatus being operated in response to thereception at the remote station of a preassigned disconnect signaltransmitted by an operator at the near station. 1

3. A communication system having a central office connected by anormally closed loop to a subscribers station having a motor and asource of power supply normally disconnected from the motor, said systemhaving a remote control arrangement for starting the motor by connectingthe source of power supply to the motor, said remote control arrangementincluding both mechanical and electrical instrumentalities for reducingthe amount of its false operation by accidental openings of the loop,and apparatus for disconnecting the source of power supply from themotor after having been connected thereto, said apparatus being operatedin response to the reception at the subscribers station of a preassigneddisconnect signal transmitted by an operator at the central office.

4. A printing telegraph system having a first printing telegraph stationconnected by a telegraph line to a second printing telegraph stationhaving a motor and a source of power supply normally disconnected fromthe motor, said system having a remote control arrangement for startingthe motor connecting the source of power supply to the motor, saidremote control arrangement comprising instrumentalities for reducing theamount of its false operation, said instrumentalities including a relayand a pawl located at the second station, and apparatus fordisconnecting the source of power supply from the motor after havingbeen connected thereto, said apparatus being operated in response to thereception at the second station of a preassigned disconnect signaltransmitted from the first station.

5. A printing telegraph system having a near printing telegraph stationconnected by a transmission line to a remote printing telegraph stationhaving a motor and a source of power supply normally disconnected fromthe motor, said system having a remote control arrangement forconnecting the source of power supply to the motor, said remote controlarrangement comprising instrumentalities for reducing the amount of itsfalse operation, said instrumentalities including a pawl, a contact, anda lever located at the remote station, and apparatus for disconnectingthe source or" power supply from the motor after having been connectedthereto, said apparatus being operated in response to the reception atthe remote station of a preassigned disconnect signal transmitted fromthe near station.

6. A communication system having a near station connected by atransmission line to a remote station having a motor and a source ofpower supply normally disconnected from the motor, said system having aremote control arrangement for connecting the source of power supply tothe motor in response to successive openings and closures of the line byan operator at the near station a preassigned number of times, saidremote control arrangement including instrumentalities for disconnectingthe source of power supply from the motor after having been connectedthereto, said instrumentalities being operated in response to thereception at the remote station of a preassigned disconnect signaltransmitted from the near station.

'7. A printing telegraph system having a first printing telegraphstation connected by a tele- 15?? graph line to a second printingtelegraph station having a motor and a source of power supply normallydisconnected from the motor, said system having a remote controlarrangement for connecting the source of power supply to the mo- 1 torin response to a plurality of successive openings and closures of theline by an operator at the first station, and instrumentalities fordisconnecting the source of power supply from the motor after havingbeen connected thereto, said i instrumentalities including a relaylocated at the second station, said relay being operated in response tothe reception at the second station of a preassigned disconnect signaltransmitted from the first station.

8. A printing telegraph system having a central printing telegraphoffice connected by a telegraph line to a subscribers printing telegraphstation having a motor and a source of power supply normallydisconnected from the motor, said sys- '1" oflice a preassigned numberof times, and instrumentalities for disconnecting the source of powersupply from the motor after having been connected thereto, saidinstrumentalities being operated in response to the reception at thesubscribers station of a preassigned disconnect signal transmitted by anoperator at the central office.

CUTHBERT C. LANE.

